1. Technical Field
The present invention pertains to liquid compositions of fatty amines and similar products, with cation-active properties.
The amines, represented by the general formula R--NH.sub.2 in which R is a hydrocarbon radical having at least ten carbon atoms, develop not only the ordinary chemical properties that characterize the amine class, and notably a basic force comparable to that of ammonia, but also surface-active properties, notably to water/liquid hydrocarbon interfaces and very pronounced adsorption properties on mineral surfaces. Industry employs these properties on a large scale, for example, for forming aqueous emulsion of various liquids, in particular the black binders for road construction, the enrichment of ores by ore flotation, and in a general manner for the most diverse treatment of mineral surfaces such as, for example, development of an antistatic effect on polymers of fibers, dewetting of metal surfaces and reduction of their corrosion, dispersion of pigments in oils, hydrophobation of sols, reduction of the agglomeration capacity of fertilizer grains, and the like. (See Cationic Surfactants by Eric Jungermann, M. Dekker publisher, 1970).
In fact, these properties which for linguistic convenience we will subsequently refer to herein as "cation-active properties", are found to be developed at the highest level in compounds that include at least one aminated nitrogen and at least one hydrophobic group including a hydrocarbon chain with at least ten carbon atoms. These formulas correspond to a broader formula than the standard formula of fatty amines in the strict sense, and which can be represented by R--Z--NH.sub.2, in which Z is a divalent polar group. By listing several examples for the Z group, the person skilled in the art will immediately recognize very common products. With Z=aminopropyl, there are the alkylaminopropylamines, such as tallow-N-propylenediamine which is widely known in the road-building industry; with Z=oxypropyl, there are the alkyloxypropylamines, referred to as ether amines, used in flotation; with Z=amidoethyl, there are the amidoamines and their cyclization products the imidazolines, largely employed as adhesivity doping agents for paving roads and the like.
2. Prior Technology
However, because of the existence of a long chain required for the development of these particular properties, these products have a relatively high melting point, and the corresponding industrial products generally have a pasty consistency at room temperature. This is an annoying characteristic from various points of view.
In the first place, transfers of these products in this form are limited to manual manipulations, which are not free from danger. They are, in fact, very aggravating for the skin and mucosa and not free from general toxicity.
Melting of these products occurs at relatively low temperatures, and the melted forms at 40.degree.-60.degree. C. are definitely very fluid, and thus can be pumped and dosed with precision equipment, avoiding all bodily contact. But, at these temperatures, they frequently emit caustic volatile products (ammonia, methylamine, propylamine, etc.), originating either from the industrial impurities which are almost obligatory in this type of compounds, or from the degradation products arising from their heating and their storage even for short periods at the temperatures that they need to reach in order to be sufficiently liquid. It is necessary to add that this melting at relatively low temperatures is difficult to carry out in industrial practice without the risk of overheating, and that in any case, such melting operations are extremely lengthy because of the well-known poor thermal exchange capacity of the fatty compounds.
Fluid compositions have been realized at room temperature by employing solvents. Leaving aside the effect of loss of efficacy related to dilution, other disadvantages of the use of solvents are well known, such as the heavy solvents are found, useless or undesirable, in the final products and the light solvents can certainly be eliminated but are also sources of flammability and/or pollution. In addition, formulations of long-chain cation-active compounds in solvents generally do not exhibit satisfactory behavior when stored at low temperatures, as will be shown below.
The chemist will know how to implement certain modifications of these molecules in order to reduce their melting points. This is what was done by oxyalkylation of alkylamines and alkylpropylenediamines, as is described for example in U.S. Pat. No. 2,930,701, in which concentrated compositions for shampoos were realized using totally oxyethylated chlorhydric solutions of oleylpropylenediamines. But it is also known that oxyalkylation results in the sacrifice of part of the cation-active properties. This has been more-or-less resolved by judicious selection of the nature of the oxyalkylene substituent and of the molar ratio of oxyalkylation (see, for example, French Patent No. 1,462,981, which discloses alkylpropylenediamines oxyethylated on the internal nitrogen, French Patent No. 1,266,909, which divulges oxyethylated tallow-or soya-propylenediamines, or French Patent Appln. No. 80,22932, which divulges compositions based on oxypropylated tallow-propylenediamines). In truth, these modification, even effected carefully, can result in an acceptable liquidity at room temperature, but this liquidity is not maintained during storage at negative temperatures. These products can be stored in barrels in the open air or under non-climate-controlled shelters. Concretions then appear, which persist for a long time after restoration of milder temperatures. The result is a segregation of the products with noteworthy differences in composition between the melted products and the concretions. These undesired phenomena also occur with the formulations in solvent that were discussed above, and also with formulations resulting from the combination of an amine in liquid form with a pasty or solid amine, such as the compositions disclosed in U.S. Pat. No. 3,975,295, of tallow-diamines with alkylamines oxyethylated in the presence of absence of alcohol solvents.
More recently (see French Patent Appl. No. 80,07091), success has been achieved in greatly reducing the melting point of N-tallow-propylenediamines without perceptibly changing their cation-active behavior by methylation of the secondary nitrogen, but these N-alkyl-N-methylpropylenediamines exhibit a negative ability to very quickly absorb the carbon dioxide and water from the atmosphere by yielding abundant concretions, such that these products lose their liquidity by simple exposure or handling in open air.